Field of the Invention
The invention relates to a method and a device for performing worksteps on a cylinder of a printing press and, more particularly, while an operating medium is being supplied, the worksteps being performed by at least one actuator energizable by the operating medium and acting against operating elements energized by spring force.
A multiplicity of worksteps are performed on cylinders of a printing press, such as clamping and tensioning of printing plates, correction of the position of printing plates, mounting or locking of coverings or other worksteps. For a long time, such worksteps were performed manually until the trend went in the direction of increasing automation. In the course of this development, actuators were disposed in the cylinders and performed such worksteps when energized with an operating medium. Usually, such actuators act against operating elements energized by spring force. Devices of this type have become known heretofore, for example, from published German Patent Documents DE 41 29 831 A1 and DE 41 28 994 A1. The former document relates to a clamping device for clamping the printing-plate leading edge, and the latter document to a clamping and tensioning device which clamps the rear or trailing edge of a printing plate, the leading edge of which has already been clamped, and then subjects the printing plate to tension.
In the aforementioned devices, it is necessary to provide an actuator, such as a pneumatic cylinder, for example, for each workstep and to energize each of the actuators with an operating medium. It is thus necessary to provide for each actuator a supply of operating medium which has to be brought into the cylinder by means of a rotary lead-through. The rotary lead-throughs for a plurality of operating-medium supply lines are elaborate, expensive and susceptible to fault or failure.